Here are some generic tips on finding the actual cause of “Backend Fetch Failed” error shown by Varnish Cache. Continue reading
Feb 06 2020
Managing of Varnish backends
This article explains how you can manage Varnish backends from command line, check varnish backend health status and mark backends as healthy or sick without restarting or reloading Varnish. Continue reading
Feb 06 2020
Varnish Backend fetch failed Too many headers
This article describes particular case of Varnish error Backend fetch failed Too many headers. This error happens when there are too many headers being sent to backend server. Here is how you can troubleshoot and fix this error. Continue reading
Feb 02 2020
FlexiSip installation and configuration on Debian 9
Flexisip is a complete, modular and scalable SIP server suite written in C++11, comprising proxy, presence and group chat functions.
Flexisip offers an easy-to-install SIP server solution, offering all the features required to deploy your own SIP service tuned for mobile or desktop applications, “out of the box”.
Flexisip can be integrated into your SIP infrastructure for various purposes : Continue reading
Feb 02 2020
Flexisip error Failed to find shared library for backend mysql
I installed Flexisip using official documentation , installed additional components like MariaDB (MySQL) and Redis, performed initial setup of configuration files, created database and DB user.
I started flexisip services with
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systemctl start flexisip-proxy flexisip-presence flexisip-conference |
and by looking in /var/opt/belledonne-communications/log/flexisip/flexisip-conference.log I noticed the following error:
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2020-02-02 03:12:30:790 liblinphone-message-Linphone core [0x56197d8a7d60] notified [global_state_changed] 2020-02-02 03:12:30:790 liblinphone-message-No charset defined forcing utf8 4 bytes specially for conference subjet storage 2020-02-02 03:12:30:790 liblinphone-message-Opening linphone database db=xxx user=xxx password='xxx' host=127.0.0.1 charset=utf8mb4 with backend Mysql 2020-02-02 03:12:30:791 liblinphone-warning-Unable to build db session with uri: Failed to find shared library for backend mysql 2020-02-02 03:12:30:791 liblinphone-error-Unable to open linphone database with uri db=xxx user=xxx password='xxx!' host=127.0.0.1 charset=utf8mb4 and backend Mysql 2020-02-02 03:12:30:791 bctbx-error-Linphone Core couldn't start because the connection to the database has failed |
Jan 24 2020
Magento server performance configuration
There are best practices in Magento 2 performance configuration of operating system, MySQL, PHP and webserver. This article covers important configurations of all components that will speed up the Magento site.
Jan 24 2020
DDoS Protection With IPtables
There are different ways of building your own anti-DDoS rules for iptables. This guide will describe comprehensive approach to protect server from DDoS attacks:
- Select the best iptables table and chain to stop DDoS attacks
- Tweak your kernel settings to mitigate the effects of DDoS attacks
- Use iptables to block most TCP-based DDoS attacks
- Use iptables SYNPROXY to block SYN floods
Here we’ll only cover protection from TCP-based attacks. Most UDP-based attacks are amplified reflection attacks that will exhaust the network interface card of any common server. Continue reading
Jan 10 2020
Selenium error: Chrome failed to start: exited abnormally
When I launched Selenium tests In Jenkins with Maven on CentOS 7 I got:
unknown error: Chrome failed to start: exited abnormally
(unknown error: DevToolsActivePort file doesn’t exist)
(The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)
Full error:
org.openqa.selenium.WebDriverException:
unknown error: Chrome failed to start: exited abnormally
(unknown error: DevToolsActivePort file doesn't exist)
(The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)
Build info: version: '3.141.59', revision: 'e82be7d358', time: '2018-11-14T08:17:03'
System info: host: 'testenv', ip: '192.168.3.33', os.name: 'Linux', os.arch: 'amd64', os.version: '3.10.0-693.17.1.el7.x86_64', java.version: '1.8.0_152'
Driver info: driver.version: ChromeDriver
remote stacktrace: #0 0x561bcf9f2479
Continue reading
Jan 06 2020
Ergo B501 flashing and malware cleaning
In addition to its good performance and capacitive battery, at an attractive price, the Ergo B501 firmware has several apk built-in that force the advertisement to load after some time using the device. The latest official firmware at the moment: Ergo B501_OS3.0 Lite_20171117 .
You can get rid of viruses in Ergo B501 by flashing a virus-free firmware. Continue reading
Jan 03 2020
Disk Encryption on CentOS using LUKS Cryptsetup
LUKS (Linux Unified Key Setup) is the standard for Linux hard disk encryption. By providing a standard on-disk-format, it does not only facilitate compatibility among distributions, but also provides secure management of multiple user passwords. In contrast to existing solution, LUKS stores all setup necessary setup information in the partition header, enabling the user to transport or migrate his data seamlessly. (source: http://code.google.com/p/cryptsetup/) Continue reading
Stay tuned! :)
